hi I have graduated from high school and now I am gonna apply to Cleveland state university to study Electrical engineering. anyway,I will have about 5 months before starting classes so I will need to strength my math foundation for calculus. I bought Precalculus for dummies but I figured out it gives you superficial information so I decided to use another book. I have found this one: Precalculus (an investigation of functions) ,it is a free book and here is the website: http://www.opentextbookstore.com/precalc/ I would appreciate it if you make a look and tell me what do you think. I would appreciate it if you have any other recommendations.